The present invention relates to power steering apparatus for producing a steering assist force by hydraulic pressure.
A patent document 1 (Japanese Patent Application Publication No. 2001-55153) shows power steering apparatus including a housing, a power cylinder enclosing a piston, a control valve, a sector gear. A patent document 2 (U.S. Pat. No. 6,415,885 corresponding to Japanese Patent Application Publication No. 2001-219858) shows power steering apparatus including a steering damper valve provided in a cylinder.